Reclaiming used lubricating oil

Abstract

A method for purifying used oil without the use of hydrogen comprising contacting a demetallized used oil with an acid such as sulfuric acid and an adsorbent such as clay.

What is claimed is: 
     
       1. A process for reclaiming demetallized used lubricating oil comprising treating said demetallized oil with acid to clear the oil, contacting the acid treated clear oil with an adsorbent to decolorize and deodorize said clear oil. 
     
     
       2. A process according to claim 1 wherein said acid is concentrated sulfuric acid in the concentration range of about 1 to about 5 volume percent and said adsorbent is clay in the concentration range of about 0.2 to about 1 pound of clay per gallon of oil. 
     
     
       3. A process according to claim 2 wherein the amount of said sulfuric acid is about 2 volume percent concentrated acid based on the volume of oil. 
     
     
       4. A process for the production of an essentially pure oil stock from a used lubricating oil containing undesirable components comprising: (a) contacting said used lubricating oil with a demetallizing agent to form an oil phase essentially free of metal contaminants;   (b) contacting the now demetallized oil from step (a) with a relatively small amount of concentrated acid;   (c) allowing the acid treated oil of (b) to phase separate into an oil phase and an acid phase;   (d) contacting the resulting oil phase from step (c) with at least one adsorbent selected from the group consisting of activated carbon, silica gel, clay, bauxite and alumina;   (e) separating the oil and particles from step (d) resulting in a finished clear oil product.   
     
     
       5. A process according to claim 4 wherein said acid is sulfuric acid in the concentration of less than about 6 volume percent concentrated acid based on the volume of oil. 
     
     
       6. A process according to claim 5 wherein the amount of said sulfuric acid is about 2 volume percent concentrated acid based on the volume of oil. 
     
     
       7. A process according to claim 4 wherein said adsorbent is in the range of about 0.2 to about 1 pound per gallon of oil. 
     
     
       8. A process according to claim 4 wherein said settled oil is contacted with said adsorbent in the temperature range of about 250° to 450° F. 
     
     
       9. A process according to claim 4 wherein said adsorbent is clay that decolorizes and deodorizes said oil. 
     
     
       10. A process for the production of essentially pure oil stock from a used lubricating oil containing undesirable components comprising: (a) contacting said used lubricating oil with an aqueous solution of a treating agent capable of reacting with essentially all of the ash-forming metal constituents in said used lubricating oil rendering them removable under conditions sufficient to disperse said agent in said lubricating oil and reacting a sufficient amount of said agent with said metals of said lubricating oil;   (b) removing a major portion of the water from the mixture resulting from combining said aqueous solution and said lubricating oil;   (c) separating solids from the oil resulting from step (b) to obtain a demetallized partially purified oil;   (d) contacting said demetallized partially purified oil of step (c) with a relatively small amount of concentrated sulfuric acid;   (e) settling the mixture of step (d) to form an oil phase and an acid phase;   (f) contacting the resulting settled oil from step (e) with at least one adsorbent selected from the group consisting of activated carbon, silica gel, clay, bauxite and alumina;   (g) separating the oil and the particles from step (f) by filtration resulting in a finished clear product.   
     
     
       11. A process according to claim 10 wherein said treating agent is comprised essentially of an ammonium salt selected from the group consisting of ammonium sulfate, ammonium bisulfate, ammonium phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate and mixtures thereof. 
     
     
       12. A process according to claim 10 wherein the concentration of ammonium salt in said aqueous solution of a treating agent is in the range of 30 to 95 weight percent of that in an aqueous solution at 25° C. saturated with a treating agent. 
     
     
       13. A process according to claim 10 wherein said treating agent is present in an amount such that the ratio of treating agent to used lubricating oil is in the range of about 0.002:1 to about 0.05:1. 
     
     
       14. A process according to claim 10 wherein the amount of said sulfuric acid is about 2 volume percent concentrated acid based on the volume of oil. 
     
     
       15. A process according to claim 10 wherein said adsorbent is in the range of about 0.2 to about 1 pound per gallon of oil. 
     
     
       16. A process according to claim 10 wherein said adsorbent is clay that decolorizes and deodorizes said oil.